Deactivation of Staphylococcus Aureus and Escherichia Coli using Plasma Needle at Atmospheric Pressure

Non-thermal (low-temperature) plasma may act as an alternative approach to control superficial wounds and skin infections when the effectiveness of chemical agents is weak due to natural pathogen or biofilm resistance. In this paper an atmospheric pressure plasma needle jet device local made which generates a cold plasma jet 1mm diameter and about 30 mm in length sustained by low-frequency excitation was used to study the deactivation of two bacterial isolates Escherichia coli and Staphylococcus aureus. Escherichia coli and Staphylococcus aureus were used as a model system to optimize the conditions for bacterial destruction. Plasma working gas flow rate, treatment time and needle to sample distance are varied. Plasma treatment of Escherichia coli results in formation of inhibition zone of 25 mm and Staphylococcus aureus in 29 mm inhibition zone respectively. Prolongation of treatment time improves the destruction efficiency. Sample treatment during plasma treatment has been monitored. The temperature can reach up to 32ºC at shortest needle-to- sample distances and 80 s treated time where the ambient temperature was 29ºC.